According to bettercrypto.org, DSA should not be used anymore for SSH. See chapter 2.2 Applied Crypto Hardening Paper at » https://bettercrypto.org/ «.
So it's likely DSA has been removed completely now starting with OpenSSH 7.

Just to end (part of-) the speculation, have a look at the package changelog (/usr/share/doc/openssh-server/changelog.Debian.gz):

Code:

openssh (1:7.1p1-1) unstable; urgency=medium

* New upstream release (http://www.openssh.com/txt/release-7.0, closes:
#785190):
- Support for the legacy SSH version 1 protocol is disabled by default
at compile time.
- Support for the 1024-bit diffie-hellman-group1-sha1 key exchange is
disabled by default at run-time. It may be re-enabled using the
instructions at http://www.openssh.com/legacy.html
- Support for ssh-dss, ssh-dss-cert-* host and user keys is disabled by
default at run-time. These may be re-enabled using the instructions
at http://www.openssh.com/legacy.html
- Support for the legacy v00 cert format has been removed.
- The default for the sshd_config(5) PermitRootLogin option has changed
from "yes" to "prohibit-password".
- PermitRootLogin=without-password/prohibit-password now bans all
interactive authentication methods, allowing only public-key,
hostbased and GSSAPI authentication (previously it permitted
keyboard-interactive and password-less authentication if those were
enabled).
- ssh_config(5): Add PubkeyAcceptedKeyTypes option to control which
public key types are available for user authentication.
- sshd_config(5): Add HostKeyAlgorithms option to control which public
key types are offered for host authentications.
- ssh(1), sshd(8): Extend Ciphers, MACs, KexAlgorithms,
HostKeyAlgorithms, PubkeyAcceptedKeyTypes and HostbasedKeyTypes
options to allow appending to the default set of algorithms instead of
replacing it. Options may now be prefixed with a '+' to append to the
default, e.g. "HostKeyAlgorithms=+ssh-dss".
- sshd_config(5): PermitRootLogin now accepts an argument of
'prohibit-password' as a less-ambiguous synonym of 'without-
password'.
- ssh(1), sshd(8): Add compatability workarounds for Cisco and more
PuTTY versions.
- Fix some omissions and errors in the PROTOCOL and PROTOCOL.mux
documentation relating to Unix domain socket forwarding.
- ssh(1): Improve the ssh(1) manual page to include a better description
of Unix domain socket forwarding (closes: #779068).
- ssh(1), ssh-agent(1): Skip uninitialised PKCS#11 slots, fixing
failures to load keys when they are present.
- ssh(1), ssh-agent(1): Do not ignore PKCS#11 hosted keys that wth empty
CKA_ID.
- sshd(8): Clarify documentation for UseDNS option.
- Check realpath(3) behaviour matches what sftp-server requires and use
a replacement if necessary.
* New upstream release (http://www.openssh.com/txt/release-7.1):
- sshd(8): OpenSSH 7.0 contained a logic error in PermitRootLogin=
prohibit-password/without-password that could, depending on
compile-time configuration, permit password authentication to root
while preventing other forms of authentication. This problem was
reported by Mantas Mikulenas.
- ssh(1), sshd(8): Add compatibility workarounds for FuTTY.
- ssh(1), sshd(8): Refine compatibility workarounds for WinSCP.
- Fix a number of memory faults (double-free, free of uninitialised
memory, etc) in ssh(1) and ssh-keygen(1). Reported by Mateusz
Kocielski.
* Change "PermitRootLogin without-password" to the new preferred spelling
of "PermitRootLogin prohibit-password" in sshd_config, and update
documentation to reflect the new upstream default.
* Enable conch interoperability tests under autopkgtest.

Look into the key-files under ~/.ssh/, you'll see "-----BEGIN RSA PRIVATE KEY-----" or "ssh-rsa" for the public key, compared to "-----BEGIN DSA PRIVATE KEY-----" or "ssh-dss" respectively; most of the time, the key naming will also tell you.